The effectiveness of far-infrared irradiation on foot skin surface temperature and heart rate variability in healthy adults over 50 years of age: A randomized study.

BACKGROUND: Far-infrared irradiation (FIR) is used in the medical field to improve wound healing, hemodialysis with peripheral artery occlusive disease, and osteoarthritis but seldom used in ameliorating poor lower extremity circulation. The purpose of this study was to evaluate the effect of FIR on changes in foot skin surface temperature (FSST) and autonomic nerve system (ANS) activity to evaluate its effectiveness in improving lower limb circulation. METHODS: A randomized controlled study was conducted. Subjects (n = 44), all over the age of 50 years and satisfying the inclusion criteria, were randomly allocated into 2 groups. The intervention group received FIR on a lower limb for 40 minutes and the control group received no intervention. Left big toe (LBT), right big toe (RBT), left foot dorsal (LFD), right foot dorsal (RFD) surface skin temperature, autonomic nervous activity, and blood pressure were assessed. RESULTS: The main results were skin surface temperature at the LBT increased from 30.8 ±â€Š0.4°C to 34.8 ±â€Š0.4°C, at RBT increased from 29.6 ±â€Š0.4°C to 35.3 ±â€Š0.4°C and LFD increased from 31.9 ±â€Š0.3°C to 36.4 ±â€Š0.4°C, RFD increased from 30.7 ±â€Š0.3°C to 37.7 ±â€Š0.2°C. FIR caused a significant increase of the FSST ranging in a 4°C to 7°C increase after 40 minutes irradiation (P < .001). The ANS low-frequency (LF) and high-frequency (HF) activity showed a statistically significant increase in the FIR group (P < .05) but not the LF/HF ratio. CONCLUSION: FIR significantly increased the FSST from between 4°C and 7°C after 40 minutes irradiation, which might improve lower extremity circulation and regulation of ANS activity.

Effects of Contrast Therapy Using Infrared and Cryotherapy as Compared with Contrast Bath Therapy on Blood Flow, Muscle Tone, and Pain Threshold in Young Healthy Adults.

BACKGROUND The aim of this research was to compare the effects of contrast bath therapy (CBT) and contrast therapy (CT) using infrared (IR) and cryotherapy (CR) on blood flow, muscle tone, and pain in the forearm. MATERIAL AND METHODS Twenty healthy individuals participated in this study. Each participant received 2 kinds of CT separated by a week. CBT involved immersion in hot water (38-40°C) for 4 minutes, followed by 1 minute of immersion in cold water (12-14°C) for four rotations. CT using IR and CR was performed in the same manner as CBT. RESULTS The variables measured were blood flow, muscle tone, and pain before and after intervention. Both types of CT produced fluctuations in the blood flow (P<0.05). The pain threshold increased on both therapies; a significant increase was noted with IR and CR (P<0.05) therapies. Muscle elasticity was induced and stiffness was reduced with all therapies (P<0.05). IR and CR resulted in significant changes (P<0.05) in blood flow as compared with the CBT. CONCLUSIONS The results of this study suggest that CT using IR and CR is more effective in improving blood flow than CBT and has the same effect on muscle tone and pain. Nonetheless, using IR and CR is efficient with regard to mobility and maintaining temperature; therefore, it would be convenient to use these in clinical settings. Further studies involving CT should be carried out to determine whether our findings are clinically relevant.

Does the Application of Tecar Therapy Affect Temperature and Perfusion of Skin and Muscle Microcirculation? A Pilot Feasibility Study on Healthy Subjects.

Background: Tecar therapy (TT) is an endogenous thermotherapy used to generate warming up of superficial and deep tissues. TT capability to affect the blood flow is commonly considered to be the primary mechanism to promote tissue healing processes. Despite some preliminary evidence about its clinical efficacy, knowledge on the physiologic responses induced by TT is lacking. Objective: The aim of this quantitative randomized pilot study was to determinate if TT, delivered in two modes (resistive and capacitive), affects the perfusion of the skin microcirculation (PSMC) and intramuscular blood flow (IMBF). Design: A randomized controlled pilot feasibility study. Subjects: Ten healthy volunteers (n = 4 females, n = 6 males; mean age 35.9 ± 10.7 years) from a university population were recruited and completed the study. Intervention: All subjects received three different TT applications (resistive, capacitive, and placebo) for a period of 8 min. Outcome measures: PSMC, IMBF, and the skin temperature (ST) were measured pre- and post-TT application using power Doppler sonography, laser speckle contrast imaging (LSCI), and infrared thermography. Results: Compared with placebo application, statistically significant differences in PSMC resulted after both the resistive (p = 0.0001) and the capacitive (p = 0.0001) TT applications, while only the resistive modality compared with the placebo was capable to induce a significant change of IMBF (p = 0.013) and ST (p = 0.0001). Conclusions: The use of power Doppler sonography and LSCI enabled us to evaluate differences in PSMC and IMBF induced by TT application.

Active compound chrysophanol of Cassia tora seeds suppresses heat-induced lipogenesis via inactivation of JNK/p38 MAPK signaling in human sebocytes.

BACKGROUND: Heat induced by infrared (IR) radiation from sun exposure increases skin temperature and can lead to thermal and photo-aging. However, little is known about the relationship between heat induced by IR radiation and lipid biosynthesis in human sebocytes. This study investigated the expression of factors involved in lipid biosynthesis in human sebocytes exposed to heat. The effect of Cassia tora extract and chrysophanol, which is widely used as anti-inflammatory agent, on the heat shock effect in sebocytes was then examined. METHODS: For the treatment, cells were maintained in culture medium without FBS (i.e., serum starved) for 6 h and then moved for 30 min to incubators at 37 °C (control), 41 °C, or 44 °C (heat shock). Culture media were replaced with fresh media without FBS. To investigate expression of gene and signaling pathway, we performed western blotting. Lipid levels were assessed by Nile red staining. The cytokine levels were measured by cytokine array and ELISA kit. RESULTS: We found that peroxisome proliferator-activated receptor (PPAR)γ and fatty acid synthase (FAS) were upregulated and the c-Jun N-terminal kinase (JNK)/p38 signaling pathways were activated in human sebocytes following heat exposure. Treatment with Cassia tora seed extract and chrysophanol suppressed this up-regulation of PPARγ and FAS and also suppressed the increase in IL-1ß levels. CONCLUSION: These findings provide evidence that IR radiation can stimulate sebum production; Cassia tora seed extract and chrysophanol can reverse lipid stimulated inflammatory mediation, and may therefore be useful for treating skin disorders such as acne vulgaris.

Besides Photothermal Effects, Low-Level CO2 Laser Irradiation Can Potentiate Skin Microcirculation Through Photobiomodulation Mechanisms.

Background: Improvement of microcirculation is one of the important mechanisms of low-level laser therapy (LLLT) to treat some diseases such as wound healing. Most previous studies have been carried out with multiple lasers other than the 10,600-nm CO2 laser. Recently, the CO2 laser has been used not only as a tool for excision of soft tissues but also for therapeutic applications. Objective: To study whether low-level CO2 laser irradiation can influence microcirculation and further explore the underlying mechanisms. Methods: Seventy-milliwatt (70-mW) CO2 lasers irradiated the forearms of 12 participants and skin blood perfusion (SkBP) was measured with a laser speckle imager. The thermal effect of irradiation was evaluated by measuring the irradiated skin in vivo and the exposed cell suspensions in vitro. Extracellular adenosine triphosphate (eATP) of the human mast cell line (HMC-1) is assessed by luciferin-luciferase assay to explore the potential mechanisms. Results: Irradiation caused dose-dependent increase in SkBP. At a medium dose of 262 J/cm2, SkBP reached its maximum value at 195.8% ± 18.6% of the baseline (n = 12, p < 0.01). Such laser irradiation had a mild thermal effect, heating local skin temperature (SkT) by 6.1°C ± 0.3°C (n = 10) and warming cell suspensions by 4.5°C ± 0.8°C (n = 6). Irradiation dose-dependently lowered eATP levels of HMC-1 cells in vitro. At a medium dose of 262 J/cm2, eATP levels declined to the minimum at 74.8% ± 5.5% of the baseline (n = 12, p < 0.01). This downregulation effect could be significantly inhibited by 100-µM ARL67156, a nonspecific ecto-ATPase inhibitor. On the contrary, heating itself slightly raised the level of eATP. Conclusions: Low-level CO2 laser irradiation can improve microcirculation. Besides the thermal effect, regulation of extravascular eATP by the photobiomodulation mechanism may be involved. This implies that CO2 lasers might be used in LLLT.

Effects of Footbaths with Mustard, Ginger, or Warm Water Only on Objective and Subjective Warmth Distribution in Healthy Subjects: A Randomized Controlled Trial.

OBJECTIVE: To analyze the short-term thermogenic effects of footbaths with warm water alone (WA) versus when combined with medicinal powders. DESIGN: Randomized controlled trial with cross-over. INTERVENTIONS AND OUTCOMES: Seventeen healthy volunteers (mean age 22.1 years, SD = 2.4; 11 female) received three footbaths with WA or WA combined with mustard (MU) or ginger (GI) in a randomized order. Self-perceived warmth (Herdecke warmth perception questionnaire) and actual skin temperatures (thermography) were assessed before (t0), immediately after footbaths (t1), and 10 minutes later (t2). The primary outcome was perceived warmth in the feet. Secondary outcomes were warmth perception in the face, hands and overall, as well as actual skin temperature in the feet, face, and hands. RESULTS: Perceived warmth at the feet (primary outcome) increased significantly (all p's < .001) for MU and GI at t1 as well as for GI at t2 when compared to t0 with high effect sizes. At t2, GI differed significantly from WA (p < .001) and MU (p = .048). With regards to the secondary measures of outcome, no significant effects were seen for perceived warmth at the face or hands. Overall warmth was significantly higher at t1 compared to t0 (p = .01). Thermography assessments of skin temperature at the feet at t1 increased after all conditions (p < .001). No effects were seen in the face. At the hands, temperature decreased at t1 (p = .02) and t2 compared to t0 (p < .001). CONCLUSION: The present study provides preliminary evidence that mustard and ginger increase warmth perception at the feet more than warm water alone, with only the effects for GI enduring at the brief follow-up.

Tissue models for RF exposure evaluation at frequencies above 6 GHz.

Exposures to radiofrequency (RF) energy above 6 GHz are characterized by shallow energy penetration, typically limited to the skin, but the subsequent increase in skin temperature is largely determined by heat transport in subcutaneous layers. A detailed analysis of the energy reflection, absorption, and power density distribution requires a knowledge of the properties of the skin layers and their variations. We consider an anatomically detailed model consisting of 3 or 4 layers (stratum corneum, viable epidermis plus dermis, subcutaneous fat, and muscle). The distribution of absorbed power in the different tissue layers is estimated based on electrical properties of the tissue layers inferred from measurements of reflected millimeter wavelength energy from skin, and literature data for the electrical properties of fat and muscle. In addition, the thermal response of the model is obtained using Pennes bioheat equation as well as a modified version incorporating blood flow rate-dependent thermal conductivity that provides a good fit to experimentally-found temperature elevations. A greatly simplified 3-layer model (Dermis, Fat, and Muscle) that assumes surface heating in only the skin layer clarifies the contribution of different tissue layers to the increase in surface skin temperature. The model shows that the increase in surface temperature is, under many circumstances, determined by the thermal resistance of subcutaneous tissues even though the RF energy may be deposited almost entirely in the skin layer. The limits of validity of the models and their relevance to setting safety standards are briefly discussed. Bioelectromagnetics. 39:173-189, 2018. © 2018 Wiley Periodicals, Inc.

Skin color and tissue thickness effects on transmittance, reflectance, and skin temperature when using 635 and 808 nm lasers in low intensity therapeutics.

OBJECTIVE: To examine the role of skin color and tissue thickness on transmittance, reflectance, and skin heating using red and infrared laser light. METHODS: Forty volunteers were measured for skin color and skin-fold thickness at a standardized site near the elbow. Transmittance, reflectance and skin temperature were recorded for energy doses of 2, 6, 9, and 12 Joules using 635 nm (36 mW) and 808 nm (40 mW) wavelength laser diodes with irradiances within American National Standards Institute safety guidelines (4.88 mm diameter, 0.192 W/cm2 and 4.88 mm diameter, 0.214 W/cm2 , respectively). RESULTS: The key factors affecting reflectance to an important degree were skin color and wavelength. However, the skin color effects were different for the two wavelengths: reflectance decreased for darker skin with a greater decrease for red light than near infrared light. Transmittance was greater using 808 nm compared with 635 nm. However, the effect was partly lost when the skin was dark rather than light, and was increasingly lost as tissue thickness increased. Dose had an increasing effect on temperature (0.7-1.6°C across the 6, 9, and 12 J doses); any effects of wavelength, skin color, and tissue thickness were insignificant compared to dose effects. Subjects themselves were not aware of the increased skin temperature. Transmittance and reflectance changes as a function of energy were very small and likely of no clinical significance. Absorption did not change with higher energy doses and increasing temperature. CONCLUSION: Skin color and skin thickness affect transmittance and reflectance of laser light and must be accounted for when selecting energy dose to ensure therapeutic effectiveness at the target tissue. Skin heating appears not to be a concern when using 635 and 808 nm lasers at energy doses of up to 12 J and irradiance within American National Standards Institute standards. Photobiomodulation therapy should never exceed the American National Standards Institute recommendation for the maximum permissible exposure to the skin. Lasers Surg. Med. 50:291-301, 2018. © 2017 Wiley Periodicals, Inc.

Photobiomodulation laser and pulsed electrical field increase the viability of the musculocutaneous flap in diabetic rats.

The purpose of this study is to investigate the effect of pulsed electrical field (PEF) and photobiomodulation laser (PBM) on the viability of the TRAM flap in diabetic rats. Fifty Wistar rats were divided into five homogeneous groups: Group 1-control; Group 2-diabetics; Group 3-diabetics + PEF; Group 4-diabetic + laser 660 nm, 10 J/cm2, 0.27 J; Group 5-diabetic + laser 660 nm, 140 J/cm2, 3.9 J. The percentage of necrotic area was evaluated using software Image J®. The peripheral circulation of the flap was evaluated by infrared thermography FLIR T450sc (FLIR® Systems-Oregon USA). The thickness of the epidermis (haematoxylin-eosin), mast cell (toluidine blue), leukocytes, vascular endothelial growth factor, fibroblast and newly formed blood vessels were evaluated. For the statistical analysis, the Kruskal-Wallis test was applied followed by Dunn and ANOVA test followed by Tukey with critical level of 5% (p < 0.05). The PEF reduced the area of necrosis, decreased the leukocytes, increased the mast cells, increased the thickness of epidermis and increased newly formed blood vessels when it was compared to the untreated diabetic group of animals. Laser 660 nm, fluence 140 J/cm2 (3.9 J) showed better results than the 10 J/cm2 (0.27 J) related to reduction of the area of necrosis and the number of leukocytes, increased mast cells, increased thickness of the epidermis, increased vascular endothelial growth factor, increased fibroblast growth factor and increase of newly formed blood vessels in diabetic animals. The laser and pulsed electrical field increase the viability of the musculocutaneous flap in diabetic rats.

The thermal impact of phototherapy with concurrent super-pulsed lasers and red and infrared LEDs on human skin.

From the very first reports describing the method of action of phototherapy, the effects have been considered to be the result of photochemical and photophysical interactions between the absorbed photons and tissue and not related to secondary changes in tissue or skin temperature. However, thermal effects have been recently reported in dark pigmented skin when irradiated with single wavelengths of 810 and 904 nm of low-level laser therapy (LLLT) devices even with doses that do not exceed those recommended by the World Association of Laser Therapy (WALT). The aim of this study was to evaluate the thermal impact during the concurrent use of pulsed red and infrared LEDs and super-pulsed lasers when applied to light, medium, and dark pigmented human skin with doses typically seen in clinical practice. The study evaluated the skin temperature of 42 healthy volunteers (males and females 18 years or older, who presented different pigmentations, stratified according to Von Luschan's chromatic scale) via the use of a thermographic camera. Active irradiation was performed with using the multi-diode phototherapy cluster containing four 905-nm super-pulsed laser diodes (frequency set to 250 Hz), four 875-nm infrared-emitting diodes, and four 640-nm LEDs (manufactured by Multi Radiance Medical™, Solon, OH, USA). Each of the four doses were tested on each subject: placebo, 0 J (60 s); 10 J (76 s); 30 J (228 s); and 50 J (380 s). Data were collected during the last 5 s of each dose of irradiation and continued for 1 min after the end of each irradiation. No significant skin temperature increases were observed among the different skin color groups (p > 0.05), age groups (p > 0.05), or gender groups (p > 0.05). Our results indicate that the concurrent use of super-pulsed lasers and pulsed red and infrared LEDs can be utilized in patients with all types of skin pigmentation without concern over safety or excessive tissue heating. Additionally, the doses and device utilized in present study have demonstrated positive outcomes in prior clinical trials. Therefore, it can be concluded that the effects seen by the concurrent use of multiple wavelengths and light sources were the result of desirable photobiomodulation effect and not related to thermal influence.

Influence of electroacupuncture on thermal changes in a soft tissue defect.

This study investigated thermal changes in the skin at locations where soft tissue defects existed and acupuncture needles stimulated by using bipolar electroacupuncture (EA) had been inserted. Under general anesthesia (GA), experimental defects were made at the dorsum site of five New Zealand rabbits. Bipolar EA was used for 20 minutes to stimulate the experimental defects, and the skin temperature was monitored at the sites where the acupuncture needles had been inserted and the soft tissue defects existed. The initial thermography of those defects had the same trend as that of the negative pole of EA stimulation at the first acupoint. Skin thermography during the first 3 minutes of bipolar EA indicated a centrifugal vasoconstriction and a vasodilatation at the negative and positive poles, respectively. After that, the thermal change in soft tissue undergoing EA stimulation was not modified by a different EA polarity. The local temperature at the defect and its surroundings under both positive and negative electric loads was increased by 0.2-0.3 °C for vasodilatation. This study indicates that EA influences sympathetic modulation of soft tissue defects and that selective sympathetic modulation caused by bipolar EA is responsible for the clinical perception.

[Water-filtered infrared-A (wIRA) promotes wound healing]. / Wassergefiltertes Infrarot A (wIRA) hilft Wunden heilen.

Water-filtered infrared-A (wIRA) is a special form of heat radiation with high tissue penetration and low thermal load to the skin surface which promotes the healing of acute and chronic wounds both by thermal and thermic as well as by non-thermal and non-thermic effects. Water-filtered infrared-A increases tissue temperature (+ 2.7 °C at a tissue depth of 2 cm), tissue oxygen partial pressure (+ 32 % at a tissue depth of 2 cm) and tissue perfusion. These three factors are decisive for a sufficient supply of tissue with energy and oxygen and consequently also for wound healing and infection defense. Water-filtered infrared-A promotes normal as well as disturbed wound healing by diminishing inflammation and exudation, by promotion of infection defense and regeneration, and by alleviation of pain. These effects have been proven in a total of seven prospective studies (of these six randomized controlled studies) with most of the effects having an evidence level of Ia or Ib. The additional cases of complicated courses of wound healing presented in this article illustrate the proven effects of wIRA. Not only in the 6 presented cases wIRA turned the complicated courses of wound healing for the better and facilitated the healing of the wounds after varying total times of irradiation (in the 6 cases 51-550 h) and after variable times of wound care and mostly after transplantation of split skin grafts. In complicated courses of wound healing wIRA does not replace consultation and, when indicated, treatment by an experienced plastic surgeon and by a surgeon specialized in septic surgery. With these limitations wIRA can be recommended as a valuable complement for the treatment of acute as well as of chronic wounds.

Effects of far-infrared irradiation on myofascial neck pain: a randomized, double-blind, placebo-controlled pilot study.

OBJECTIVES: The objective of this study was to determine the relative efficacy of irradiation using a device containing a far-infrared emitting ceramic powder (cFIR) for the management of chronic myofascial neck pain compared with a control treatment. DESIGN: This was a randomized, double-blind, placebo-controlled pilot study. PARTICIPANTS: The study comprised 48 patients with chronic, myofascial neck pain. INTERVENTION: Patients were randomly assigned to the experimental group or the control (sham-treatment) group. The patients in the experimental group wore a cFIR neck device for 1 week, and the control group wore an inert neck device for 1 week. MAIN OUTCOME MEASUREMENT: Quantitative measurements based on a visual analogue scale (VAS) scoring of pain, a sleep quality assessment, pressure-pain threshold (PPT) testing, muscle tone and compliance analysis, and skin temperature analysis were obtained. RESULTS: Both the experimental and control groups demonstrated significant improvement in pain scores. However, no statistically significant difference in the pain scores was observed between the experimental and control groups. Significant decreases in muscle stiffness in the upper regions of the trapezius muscles were reported in the experimental group after 1 week of treatment. CONCLUSIONS: Short-term treatment using the cFIR neck device partly reduced muscle stiffness. Although the differences in the VAS and PPT scores for the experimental and control groups were not statistically significant, the improvement in muscle stiffness in the experimental group warrants further investigation of the long-term effects of cFIR treatment for pain management.

Effects of temperature-dependent optical properties on the fluence rate and temperature of biological tissue during low-level laser therapy.

The effects of temperature-dependent optical properties on the change of fluence rate and temperature distribution within biological tissues during low-level laser therapy (LLLT) were investigated by experimental and numerical methods. The fluence rate and temperature within a porcine skin were measured in vitro using an optical fiber sensor and a thermocouple, respectively, while irradiating the sample with a continuous wave laser (IPG Laser GmbH, Burbach, Germany, 1,064 nm, 3.14 W/cm(2)). The absorption and reduced scattering coefficients of porcine skin were estimated using an inverse adding-doubling algorithm from the total reflectance and transmittance measured with a double-integrating sphere. It was shown that the reduced scattering coefficient of porcine skin decreased significantly as the skin temperature increased within the range of 26-40 °C. To incorporate the temperature dependency of tissue optical properties in the simulation, a mathematical model that adopted coupled equations for fluence rate and bioheat transfer was developed. It was shown that the predicted fluence rate and temperature by the proposed mathematical model agreed closely with the measured values of porcine skin. The calculation of human skin temperature using the developed model revealed that the skin temperature could be significantly underestimated if the temperature dependency of optical properties of human skin were ignored during LLLT simulation.

Biodegradable magnesium nanoparticle-enhanced laser hyperthermia therapy.

BACKGROUND: Recently, nanoparticles have been demonstrated to have tremendous merit in terms of improving the treatment specificity and thermal ablation effect on tumors. However, the potential toxicity and long-term side effects caused by the introduced nanoparticles and by expelling them out of the body following surgery remain a significant challenge. Here, we propose for the first time to directly adopt magnesium nanoparticles as the heating enhancer in laser thermal ablation to avoid these problems by making full use of the perfect biodegradable properties of this specific material. METHODS: To better understand the new nano "green" hyperthermia modality, we evaluated the effects of magnesium nanoparticles on the temperature transients inside the human body subject to laser interstitial heating. Further, we experimentally investigated the heating enhancement effects of magnesium nanoparticles on a group of biological samples: oil, egg white, egg yolk, in vitro pig tissues, and the in vivo hind leg of rabbit when subjected to laser irradiation. RESULTS: Both the theoretical simulations and experimental measurements demonstrated that the target tissues injected with magnesium nanoparticles reached much higher temperatures than tissues without magnesium nanoparticles. This revealed the enhancing behavior of the new nanohyperthermia method. CONCLUSION: Given the unique features of magnesium nanoparticles--their complete biological safety and ability to enhance heating--which most other advanced metal nanoparticles do not possess, the use of magnesium nanoparticles in hyperthermia therapy offers an important "green" nanomedicine modality for treating tumors. This method has the potential to be used in clinics in the near future.

[The influence of ultrahigh-frequency electromagnetic radiation and low-intensity laser radiation on the body core temperature and basal metabolism in rats with systemic inflammation].

The effects of ultrahigh-frequency electromagnetic radiation (UHF EMR) and low-intensity laser irradiation (LILI) on the body and skin temperature, oxygen consumption, production of carbon dioxide and heat release were investigated in the experiments on intact rats and during LPS-induced polyphasic fever. It was found that UHF EMR with the wavelength of 4,9 mm, 5,6 mm or 7,1 mm and LILI with the wavelength of 0.47 microm, 0.67 microm and 0.87 microm caused modulation of basal metabolism and thermal response to systemically administered lipopolysaccharide (LPS). These findings suggest that the most pronounced antipyretic and hypometabolic effects were observed after the treatment with UHF EMR at 7,1 mm and LILI at 470 microm.

Análise termográfica da região de masseter após irradiação com laser ou LED - estudo clínico / Infrared thermal analysis of the masseter region after irradiation with led low level laser - clinical study

Introdução: Segundo alguns estudos, a terapia com laser de baixa intensidade pode promover modificações na microcirculação periférica. Objetivo: Busca-se, por meio desse estudo analisar a temperatura facial após ser submetida a irradiação com laser e LED. Métodos: Nove voluntários, com idade média de 28 anos, receberam radiação com laser (660 nm, 30 mW, 7,5 J/cm2, 10 segundos) ou LED (640±20 nm, 30 mW, 4 J/cm2, 20 segundos). Resultados: O lado contralateral (controle) das terapias não apresentou diferenças significativas pós-irradiação. Conclusão: Pode-se sugerir que, nas doses testadas, não existiram efeitos sistêmicos sobre a temperatura superficial pós-irradiação. As terapias com os parâmetros utilizados (teste) para o laser não promoveram diferença significativa na temperatura superficial local, no entanto, para o LED pode apresentar efeito modulador da temperatura periférica em até 5 minutos pós-irradiação, podendo auxiliar no pós- operatório, porém necessita de mais estudos.

Introduction: According to some studies, therapy with low-intensity laser can promote changes in peripheral microcirculation. Objective: The aim is, through this study to analyze the facial temperature after being subjected to irradiation with laser and LED. Methods: Nine volunteers, mean age 28 years, received radiation laser (660 nm, 30 mW, 7.5 J/cm2, 10 seconds) or LED (640 ± 20 nm, 30 mW, 4 J/cm2, 20 seconds). Results: The contralateral (control) of therapy showed no significant differences in post-irradiation. Conclusion: The results suggest that, at the dose tested, there were no systemic effects on the surface temperature post-irradiation. Therapies with the parameters used (test) for the laser did not cause significant difference in local surface temperature, however, the LED may have a modulatory effect of peripheral temperature within 5 minutes after irradiation, which could aid in the postoperative period, but requires further studies.

The thermal effects of therapeutic lasers with 810 and 904 nm wavelengths on human skin.

OBJECTIVE: To investigate the effect of therapeutic infrared class 3B laser irradiation on skin temperature in healthy participants of differing skin color, age, and gender. BACKGROUND: Little is known about the potential thermal effects of Low Level Laser Therapy (LLLT) irradiation on human skin. METHODS: Skin temperature was measured in 40 healthy volunteers with a thermographic camera at laser irradiated and control (non-irradiated) areas on the skin. Six irradiation doses (2-12 J) were delivered from a 200 mW, 810 nm laser and a 60 mW, 904 nm laser, respectively. RESULTS: Thermal effects of therapeutic LLLT using doses recommended in the World Association for Laser Therapy (WALT) guidelines were insignificant; below 1.5°C in light, medium, and dark skin. When higher irradiation doses were used, the 60 mW, 904 nm laser produced significantly (p < 0.01) higher temperatures in dark skin (5.7, SD ± 1.8°C at 12 J) than in light skin, although no participants requested termination of LLLT. However, irradiation with a 200 mW, 810 nm laser induced three to six times more heat in dark skin than in the other skin color groups. Eight of 13 participants with dark skin asked for LLLT to be stopped because of uncomfortable heating. The maximal increase in skin temperature was 22.3°C. CONCLUSIONS: The thermal effects of LLLT at doses recommended by WALT-guidelines for musculoskeletal and inflammatory conditions are negligible (<1.5°C) in light, medium, and dark skin. However, higher LLLT doses delivered with a strong 3B laser (200 mW) are capable of increasing skin temperature significantly and these photothermal effects may exceed the thermal pain threshold for humans with dark skin color.

Efficient 3D numerical approach for temperature prediction in laser irradiated biological tissues.

Temperature prediction in biological tissues irradiated by an optical source is frequently required in some medical applications, like Thermotherapy, Hyperthermia or tissue ablation. In this work we propose a new numerical approach to solve the bio-heat equation. It is based on the two steps 3D modified Du Fort-Frankel algorithm, which allows a better convergence, more accuracy and a faster computation than previous numerical methods developed by other authors. The model also includes adaptive spatial mesh and time step refinement. These improved results for opto-thermal temperature distribution could be used for choosing appropriate laser treatment parameters in medical praxis.

Regulation of skin collagen metabolism in vitro using a pulsed 660 nm LED light source: clinical correlation with a single-blinded study.

It has been reported that skin aging is associated with a downregulation in collagen synthesis and an elevation in matrix metalloproteinase (MMP) expression. This study investigated the potential of light-emitting diode (LED) treatments with a 660 nm sequentially pulsed illumination formula in the photobiomodulation of these molecules. Histological and biochemical changes were first evaluated in a tissue-engineered Human Reconstructed Skin (HRS) model after 11 sham or LED light treatments. LED effects were then assessed in aged/photoaged individuals in a split-face single-blinded study. Results yielded a mean percent difference between LED-treated and non-LED-treated HRS of 31% in levels of type-1 procollagen and of -18% in MMP-1. No histological changes were observed. Furthermore, profilometry quantification revealed that more than 90% of individuals showed a reduction in rhytid depth and surface roughness, and, via a blinded clinical assessment, that 87% experienced a reduction in the Fitzpatrick wrinkling severity score after 12 LED treatments. No adverse events or downtime were reported. Our study showed that LED therapy reversed collagen downregulation and MMP-1 upregulation. This could explain the improvements in skin appearance observed in LED-treated individuals. These findings suggest that LED at 660 nm is a safe and effective collagen-enhancement strategy.